Flustered
by MoyaKite
Summary: Reigisa. For the prompt: "Like nagisa saying nice things about rei and rei is like blushing but nagisa isnt really trying to flirt but rei is getting really flustered and kisses him?" UPDATE: Chapter 2 for the prompt: "Rei's helping Nagisa study but it ultimately turns into a lot more." Rated T for pickup lines.
1. Chapter 1

Rei pushed up his glasses with a sigh. "Nagisa-kun, are you really trying to study?"

"Yeah." Nagisa stopped trying to balance a pencil on his nose and looked over at him. "You're just so _smart_, Rei-chan."

"I study," he said, but he looked away to hide his embarrassment. "It's nothing special."

"Are you kidding?" Nagisa said, and the earnest tone in his voice convinced Rei to turn around—the boy looked positively awestruck. "Set mass to the vector delta and calculate science?"

"None of those words made sense in that order," Rei replied. "You weren't paying attention at all, were you?"

"And your form!" Nagisa's eyes went starry. "Whether you're running or jumping or diving, you just look gorgeous."

"I can't even swim."

"And you still look better not-swimming than half the people actually-swimming at the beach." Nagisa rolled his eyes.

"Nanase-senpai is the one who makes it look natural." He tried and failed to fight down his blush.

"And you've got this incredible intensity when you're focusing." Nagisa gestured broadly with his hands, smiling off into the distance. "It's the coolest thing. You make not-swimming look _good_, Rei-chan."

"I—that's preposterous—"

"Preposterous how good you look? Uh, yeah. I think Gou-chan's gonna need a cold shower after she looks at those deltoids."

"That's—Nagisa-kun, there's no need to tease me!"

"Tease you?" He turned impossibly wide, innocent eyes on Rei, his hand pressed against his cheek in shock. "I would never tease anybody. I mean every word!"

The proximity of Nagisa's fingers to his soft, pink lips distorted the calculations running through the back of Rei's mind. He wetted his lips and tried to bring the conversation back to something he knew and understood—studying.

"If you calculate the acceleration of two objects going at vectors _a_ and _b_, respectively, you can determine at what point the objects will collide," he said, sketching a rough diagram on some notebook paper—two circles drawn together by gravity.

Nagisa pouted, and Rei felt himself sinking—the circles on the page became too real, too tangible for his theories. Two pairs of lips drawn together.

"Both objects are affected by the pull of gravity, so we must account for that," he rushed.

"But does it matter when they end up together?" Nagisa asked. He tapped the page, smudging the graphite. "Look. They're heading right for each other."

"If they miss, inertia will carry them apart. They have one chance."

"That's so sad, though." Nagisa scooted closer, frowning briefly at the page before turning sincere eyes on Rei. "You're so smart, though. Can't you get them to turn around?"

"I—If you account for outside forces acting upon—" Rei stammered, eyes flicking between Nagisa's eyes and lips, "upon the object, then—-then there is certainly the possibility that—" The possibility that Nagisa's face was rising up to meet his—or maybe his was sinking to meet Nagisa's. "—that they could—"

Their lips connected, and Rei's brain ground to a hault. He dared to peek through his lashes at Nagisa, whose eyes had gone wide, and drew back sharply in horrified embarrassment.

"I—I don't know what came over me."

"Rei-chan." Nagisa cupped his cheek to force their eyes to meet. "I don't speak science. If you want a kiss, just say so!"

"Th-that's not—"

Nagisa rolled his eyes and put on his stodgiest voice. "And now the outside force is going to act on object _a_ and make sure it collides a second time with object _b_." With that, Nagisa pulled Rei's head down and kissed him soundly on the lips. When they broke apart, he grinned. "Good thing I need science tutoring. This could be fun."


	2. Chapter 2

"This is your third tutoring session this week, and you still can't keep the terms straight."

"Inertia: an object at rest tends to stay at rest." Nagisa grinned. "Can't fight physics, right?"

"And an object in motion tends to stay in motion," Rei countered. "Once you get started, it'll be much easier to make progress."

"Unless acted upon by an outside force." Nagisa crossed his arms and stuck his chin out defiantly. "How on earth am I supposed to concentrate when I'm thinking about swimming practice?"

"And how is _that_ an outside force?" Rei rolled his eyes. "You're using terms, but you still don't know what they mean."

Nagisa sighed and shook his head. "Obviously you've never seen yourself in a speedo."

Rei choked on air. "That's—Nagisa-kun! I've told you that we need to stay on task."

"And I've told you that I need a hands on demonstration." Nagisa batted his eyelashes, the very picture of innocence. "I wish I were your derivative so I could lie tangent to your curves."

Rei spluttered, unable to formulate a reply. That line implied some actual knowledge of what a tangent was—what a derivative was, even. Something about the turnabout made it hard for him to catch his breath.

"Since distance equals velocity times time, let's let velocity and time approach infinity, because I want to go all the way with you."

"You want to—to _what_?"

The smug expression on Nagisa's face set his heart pounding. "Your beauty cannot be spanned by a finite basis of vectors."

"Enough about how beautiful I am—we're supposed to be working on this problem set!"

"I wish I could be your problem set, because then I'd be really hard, and you'd be doing me on the desk."

Rei's jaw dropped. He pushed his glasses up with shaking hands.

"Better yet," Nagisa continued, wrapping an arm around Rei's waist, "what do you say we use my lever to shift your center of mass?" He beamed. "Or if you're more into experimentation… I know the spring constant for my mattress. Wanna take some data?"

"You—I—_enough studying_." Rei snapped the textbook shut and stood sharply, using it as a rather convenient shield. "It seems like you have the subject well in hand—"

"That's not the only thing I could have well in—"

"—so I think I'll take my leave."

He turned to go, and Nagisa grabbed his hand.

"Don't tell me that I spent all week memorizing those lines and you aren't even going to kiss me!" He sounded distraught; before Rei could think better of it, he'd turned to check on him and been trapped by the saddest puppy eyes he'd ever seen.

"You—you were serious?" he asked haltingly. Remembering their first study session, his cheeks flushed. He'd taken it for a way to avoid actual work, not—not sincerity.

"Duh," Nagisa blew a curl out of his eyes. "Do you really think I'd _volunteer_ to study?"

Rei opened and closed his mouth. In retrospect, it did seem inconsistent with Nagisa's character."

"Oh, boy," Nagisa muttered. He shook his head and rose. "If an object in motion tends to stay in motion, will this kiss get our momentum going toward the bedroom?" He went to kiss Rei, then hesitated. "You _do_ want me to kiss you, right?"

Before he could stifle it, the truth came out: "Yes, of course."

Nagisa grinned. "Good." Without further warning, he hooked his leg around Rei's and sent him tumbling to the ground, pinning him against the floor. "Because I _really_ want to kiss you."

((Source for several pickup lines: . , . ))


End file.
